Conversion of chondrocyte into osteogenic cells is caused by

Growth hormone (GH) any of several related polypeptide hormones secreted by the anterior lobe of the pituitary gland that directly influences protein, carbohydrate, and lipid metabolism and controls the rate of skeletal and visceral growth; their secretion is in pa controlled by the hypothalamus.Ref: Ganong&;s review of medical physiology; 24th edition; page no: 327